Electronic flash device

Abstract

In an electronic flash device for use in a still camera, a calculation circuit means calculates a ratio of the amounts of light to be emitted by a plurality of flash light tubes on the basis of color temperature information and control circuit means controls the emission of light of the respective flash light tubes in such a manner that the ratio of light amount emitted from the respective flash light tubes corresponds to the ratio calculated by the calculation circuit means.

What is claimed is: 
     
       1. An electronic flash device for use in a still camera, said device comprising: means for producing color temperature information;   at least two flash light emitting means, each of which can emit flash light having different spectral characteristics;   calculation circuit means for calculating a ratio of the amounts of light to be emitted by the respective flash light emitting means on the basis of the information fed from the means for producing the color temperature information; and   control circuit means for controlling the emission of light of the respective flash light emitting means in such a manner that the ratio of the light amount emitted from the respective flash light emitting means corresponds to the ratio calculated by the calculation circuit means.   
     
     
       2. The electronic flash device according to claim 1, wherein said device further comprises data producing means for producing light amount data representing an amount of light to be emitted from one of said flash light emitting means for a desired exposure, said calculation circuit means determines the light amount to be emitted from one of the flash light emitting means on the basis of the data fed from the data producing means and the control circuit means operates to control the flash light to the light amount determined by the operational circuit means. 
     
     
       3. The electronic flash device according to claim 1, wherein said means for producing color temperature information comprises a plurality of light measuring circuits each having a light receiving element and means for measuring the light incident on said light receiving element, said light receiving elements having different spectral sensitivity and a color temperature calculating circuit for calculating the color temperature data of the incident light on the basis of the results of the measurement by the light measurement circuits. 
     
     
       4. The electronic flash device according to claim 1, wherein said means for producing color temperature information comprises manually operated setting means for setting a desired color temperature. 
     
     
       5. The electronic flash device according to claim 1, wherein said means for producing color temperature information is adapted to produce the color temperature assigned to light sensitive elements to be used. 
     
     
       6. The electronic flash device according to claim 1, wherein said means for emitting flash light comprises three flash tubes associated with different color filters respectively. 
     
     
       7. The electronic flash device according to claim 6, wherein said flash tubes are xenon tubes. 
     
     
       8. The electronic flash device according to claim 1, wherein said means for producing color temperature information includes a manual means for setting a datum of a color temperature and means for generating a signal corresponding to the set datum. 
     
     
       9. The electronic flash device according to claim 8, wherein said manual means is settable to one of the positions correpsonding to the spectral sensitivity characteristic of a light sensitive material for the picture taking. 
     
     
       10. The electronic flash device according to claim 8, wherein said manual means is settable to positions corresponding to different types of films with respect to the color temperature suitable for each film. 
     
     
       11. An electronic flash device for use with a still camera, said device comprising: means for producing color temperature information;   at least two flash light emitting means each of which can emit light having different spectral characteristics;   first flash control means provided for controlling the starting and stopping of the light emission of one of the flash light emitting means;   second light measuring means for measuring the amount of light emitted from said one of the flash light emitting means;   light amount calculating means for calculating the amount of light to be emitted by the remaining flash light emitting means on the basis of a value defined by the amount of light measured by the second light measuring means and the color temperature information; and   second flash control means for controlling the starting and stopping of the remaining flash light emitting means on the basis of the result of the calculation in the light amount calculation means.   
     
     
       12. The electronic flash device according to claim 11, wherein said first flash control means comprises light measuring means for measuring the light reflected from an object illuminated by the flash light of the first flash light emitting means; and means for producing a control signal to stop the flash light of said one of the flash light emitting means when the light amount measured by the light measuring means attains a predetermined value.   
     
     
       13. The electronic flash device according to claim 11, wherein said means for producing color temperature information comprises a plurality of light measuring circuits each having a light receiving element and means for measuring the light incident on said light receiving elements, said light receiving elements having different spectral sensitivity and a color temperature calculating circuit for calculating the color temperature data of the incident light on the basis of the results of the measurement by the light measurement circuits. 
     
     
       14. The electronic flash device according to claim 11, wherein said means for producing color temperature information comprises manually operated setting means for setting a desired color temperature. 
     
     
       15. The electronic flash device according to claim 11, wherein said means for producing color temperature information includes a manual means for setting a datum of a color temperature and means for generating a signal corresponding to the set datum. 
     
     
       16. The electronic flash device according to claim 11, wherein said means for emitting flash light comprises two flash tubes with different color filters attached respectively. 
     
     
       17. The electronic flash device according to claim 16, wherein said flash tubes are xenon tubes. 
     
     
       18. An electronic illuminating device for cameras comprising: means for measuring the amount of red, blue and green color in an ambient light object scene and producing corresponding color signals;   means for producing color temperature signals from the color signals to calculate the desired quantity of each light to be added to the ambient light to produce a uniform color tone of the desired scene to be recorded including means for taking into consideration the spectral characteristics of the recording medium;   means for selectively emitting light of a red, blue and green color; and   means for controlling the total quantity of one color light produced by the emitting means as a function of the total quantity of another color predetermined from the means for producing color temperature signals and a ratio of the actually measured light of those respective colors.   
     
     
       19. The invention of claim 18 wherein the means for emitting light is a flash device that sequentially emits light of different colors. 
     
     
       20. The invention of claim 19 further including a light mixing box for receiving each colored light. 
     
     
       21. The invention of claim 19 wherein the means for controlling produces a signal to stop the emitting means from emitting a particular color when the predetermined quantity of that color for producing a uniform color tone has been reached. 
     
     
       22. The invention of claim 18 further including a timing means wherein the remaining colors are emitted after a predetermined time period if the quantity of a preceding color being emitted does not reach its predetermined value. 
     
     
       23. The invention of claim 22 further including a warning device to indicate the failure of the means for emitting light to provide a sufficient quantity of a particular color. 
     
     
       24. An auxiliary illumination lighting device to assist in recording color images of an object scene comprising: means for measuring the amount of ambient light of different spectral values and producing corresponding signals;   means for providing color temperature information from the measured signals to enable a uniform color tone of the desired scene to be recorded;   at least two separate sources of light for emitting light of different spectral characteristics, and   automatic means for controlling the total quantity of light of one spectral characteristic as a function of a total quantity of the other spectral characteristic light predetermined from the means for providing color temperature and a ratio of the actually measured light of each spectral characteristic.